[Expression and significance of DNA methyltransferase in sera of patients with lung cancer].

Objective: To explore the protein expressions of DNMT1, DNMT3a and DNMT3b in sera of lung cancer patients.

Methods: Enzyme-linked immunosorbent assay (ELISA) method was used to measure the protein expressions of DNMT1, DNMT3a and DNMT3b in 136 lung cancer patients hospitalized at Department of Respiratory Diseases, First Affiliated Hospital, Zhengzhou University during September 2012 to June 2013. And 147 healthy controls were selected from a population of physical examination at Sixth People's Hospital of Zhengzhou. And the relationship was analyzed between protein expressions of DNMT1, DNMT3a and DNMT3b and clinic characteristics of lung cancer.

Results: The protein expressions of DNMT1, DNMT3a and DNMT3b in patients with lung cancer (15 ± 10, 997 ± 76 , 302 ± 25) were higher than those of the controls (13 ± 10, 344 ± 93, 108 ± 22). And there were statistical significance (t = 3.28, 62.51, 37.27; P = 0.021, 0.000, 0.000). The results of Logistic regression show that the protein expressions DNMT1, DNMT3a and DNMT3b increased morbidity for lung cancer (χ(2) = 14.811, 26.768, 12.057; P = 0.000, 0.000 0.001), especially so for DNMT1 (OR = 1.545, 95%CI: 1.238-1.928). No correlation existed between the protein expressions of DNMT1, DNMT3a, DNMT3b and histological types or stages (P > 0.05).

Conclusions: The high protein expressions of serum DNMT1, DNMT3a and DNMT3b increase morbidity for lung cancer. And these markers may predict the early occurrence of lung cancer.